The co-hosts of a US morning talk show have struck back at abusive tweets from President Donald Trump.

Joe Scarborough and Mika Brzezinski claimed Mr Trump lied about a previous encounter in a tweet and said his "unhealthy obsession" with their Morning Joe programme does not serve his mental health or the country well.

The two MSNBC personalities postponed a holiday to respond to Mr Trump's tweet, which drew broad condemnation after he called Ms Brzezinski "crazy" and claimed she was "bleeding badly from a face-lift" when he saw them at his Florida estate in December.

"It's been fascinating and frightening and really sad for our country," she said on the programme.

"We're okay," said Mr Scarborough, her co-host and fiance. "The country's not."

The hosts, who also published a column on the Washington Post website on Friday, said they had known Mr Trump for more than a decade and had "fond memories" of their relationship, but that he has changed in the past two years.

They visited his Mar-a-Lago estate in Florida in late December to encourage Mr Trump to give them an interview.

Ms Brzezinski, who said she is alarmed at how the president deals with women who disagree with him, added that she believes her teasing about a Washington Post story about fake Time magazine covers with Mr Trump's face hanging at his golf facilities is what precipitated the latest Twitter attack.

"It is unbelievably alarming that this president is so easily played, he is easily played by a cable news host," she said.

"What does that say to our allies? What does that say to our enemies?"

They said Mr Trump was lying about Ms Brzezinski having a face-lift, although "she did have a little skin under her chin tweaked".

Their programme and Mr Trump have had a chequered relationship. They were criticised by some for being too close to him during the election campaign and giving his candidacy an early boost, but have turned sharply against him.

Ms Brzezinski in recent weeks has wondered whether Mr Trump was mentally ill and said the country under his presidency "does feel like a developing dictatorship".

The hosts said they have noticed a change in his behaviour over the past few years which left them neither shocked nor insulted by the Thursday tweet.

"The guy who is in the White House now is not the guy we know," Mr Scarborough said.

Mr Trump on Thursday launched a crude attack on Ms Brzezinski, tweeting: "I heard poorly rated @Morning-Joe speaks badly of me (don't watch anymore). Then how come low I.Q. Crazy Mika, along with Psycho Joe, came to Mar-a-Lago 3 nights in a row around New Year's Eve, and insisted on joining me. She was bleeding badly from a face-lift. I said no!"

The tweets united Democrats and Republicans in a chorus of protest that amounted to perhaps the loudest outcry since Mr Trump took office.

"Obviously I don't see that as an appropriate comment," said Republican House Speaker Paul Ryan.

One quick sync and you can read our content on the move without being online. Get regular news alerts straight to your mobile and keep up with the latest traffic and travel or breaking events as they happen via our daily live blogs.